Remotely controllable wellbore valve system

ABSTRACT

A remotely operable wellbore valve system includes a valve configured to be coupled to a wellbore conduit and to selectively close the conduit. The valve is disposed in a valve body configured to open an existing wellbore valve by longitudinal motion therethrough and to sealingly engage an interior of the existing wellbore valve. The system includes a valve actuator and a signal receiver in communication with the valve actuator. The signal receiver is configured to detect command signals transmitted from the Earth&#39;s surface and to cause the actuator to operate the valve in response to the detected command signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

Priority is claimed from U.S. Provisional Application No. 60/977,687filed on Oct. 5, 2007.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to the field of wellbore safety andcontrol valves.

More specifically, the invention relates to wellbore safety and controlvalves that can be installed in a failed wellbore valve and operatedremotely.

2. Background Art

Wellbore valves, such as subsurface safety valves, are used forcontrolling flow within a well tubing string suspended within awellbore. Typically, valves of this type include a valve member that ispivotally or rotatably mounted within the bore of a tubular bodydisposed within the well tubing string for movement between open andclosed positions. The valve member is urged by a spring to its closedposition, but is typically arranged to be moved to the open position inresponse to the supply of hydraulic fluid pressure from a remote sourceat the Earth's surface. The hydraulic fluid pressure acts on a pistonforming part of or associated with the valve member. Ordinarily, thevalve member is arranged to close automatically under the force of thespring in response to the exhaust of such hydraulic fluid pressure, forexample, in the event of failure of a monitored condition in or aboutthe well.

Other types of valves may be remotely operable, such as by applyingpressure signals to a fluid annulus between a wellbore casing and acoaxial tubing string. Such valves are described, for example, in U.S.Pat. No. 4,796,699 issued to Upchruch et al. and include a power supplyassociated with a valve operator proximate the valve in the wellbore, asignal receiver and a controller that causes the valve operator to openor close the valve in response to signals transmitted from the surface.

Many such valves are tubing safety valves wherein the body of the valveis disposed within the well tubing string for controlling flowtherethrough. Such valves may be of a type in which the valve body isretrievable from within the tubing string, or in which the body isconnected as part of the tubing string, i.e., tubing mounted. Typically,such a valve is a flapper pivotally mounted in the bore of the valvebody and arranged to be moved to the open position by a flow tube withwhich an hydraulic piston cooperates to move the flow tube within thebore. Thus, the supply of hydraulic fluid pressure lowers the flow tubeto force the flapper to the open position. A spring opposingly acts onthe piston to raise the flow tube and thus permit the flapper to closeupon the exhaust of hydraulic fluid pressure on the piston.

U.S. Pat. No. 3,799,258 shows a typical tubing mounted valve of thistype wherein the piston is an annular piston disposed about the flowtube within an annular pressure chamber between the flow tube and valvebody. The piston urged to its closed position, enabling the flapper toclose, by means of a coil spring compressed between the valve body andthe flow tube. However, when valves of this type are installed at greatdepths, it is difficult for a coil or similar metal spring of acceptablesize and strength to overcome the hydrostatic head of the hydraulicfluid in the control line leading to the pressure chamber, and thusraise the flow tube to permit the flapper to close.

In the event of failure of the control line and/or the valve actuator,the valve will close. Valve closure causes the well to cease producingfluid until which time the well can be repaired. Such loss of productioncan be costly. Further, repairing a failed wellbore valve in a well thatis capable of producing fluid is difficult and expensive Typically thewell must be “killed” by pumping fluid having sufficient density tocause the producing subsurface formations to stop moving fluid into thewellbore, or a “snubbing unit” or similar device must be used thatenables the wellbore production tubing to be removed while the wellborehas substantial pressure at the surface.

There exists a need for a replacement and/or repair valve that can beinserted into a defective valve body and operated remotely.

SUMMARY OF THE INVENTION

A remotely operable wellbore valve system according to one aspect of theinvention includes a valve configured to be coupled to a wellboreconduit and to selectively close the conduit. The valve is disposed in avalve body configured to open an existing wellbore valve by longitudinalmotion therethrough and to sealingly engage an interior of the existingwellbore valve. The system includes a valve actuator and a signalreceiver in communication with the valve actuator. The signal receiveris configured to detect command signals transmitted from the Earth'ssurface and to cause the actuator to operate the valve in response tothe detected command signals

Other aspects and advantages of the invention will be apparent from thefollowing description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a surface (wellhead) control system for a remotely operablewellbore valve.

FIG. 2 shows a typical prior art hydraulically operated wellbore valve.

FIG. 3 shows one example of a wellbore valve system according to theinvention.

DETAILED DESCRIPTION

U.S. Pat. No. 6,899,178 issued to Tubel et al. discloses an acousticwireless communication device for transmitting signals from a wellboreto the Earth's surface. The principle of the device disclosed in theTubel et al. '178 patent may be used to transmit control signals fromthe Earth's surface to a valve controller disposed in the wellbore. Theacoustic based wireless communication device is able to transmit data tothe surface through the wellbore tubing string, while also transmittingdata through the fluids in the wellbore.

An example of a system used to transmit command or control signals froma wellhead (typically at the Earth's surface) is shown in FIG. 1. A“tree cap” 14, which may be a threaded coupling affixable to the top ofa conventional wellhead system 14A (“christmas tree”), includes awireless signal transducer 10 such as an acoustic transducer. The signaltransducer receives electrical signals over a cable 12 in electricalcommunication with a control unit 11. The control unit 11 may include aprogrammable computer (not shown separately) and suitable transducerdrivers (not shown separately) configured to impart signals to thetransducer 10 so that the transducer 10 wirelessly transmits controlcommands to a valve system (FIG. 3) disposed in the wellbore.

A wireless receiver or transceiver unit (see FIG. 3) disposed in thewellbore can receive acoustic commands such as may be transmitted fromthe device shown in FIG. 1. Such commands can be of appropriatecharacter, depending on the particular application for the communicationsystem. In the present example, and as will be further explained withreference to FIG. 3, the commands sent by the wireless communicationsystem from the surface may include commands to open, maintain open orclose a valve inserted into the wellbore. In addition to or insubstitution of the wireless signal communication system shown in FIG.1, other methods of signal communication such as a communication/systeminterrogation sonde may be inserted into the wellbore device for controland/or diagnostic purposes, and such will be explained in more detailbelow with reference to FIG. 3. One method for inserting such a sondewould be at the end of armored electrical cable (wireline). See, e.g.,U.S. Pat. No. 4,806,928 issued to Veneruso.

Using any of the foregoing devices, for example, other commands that canbe sent from the surface to a device in the wellbore include commands tomaintain power supply to a device, shut off power supply to a device,regulate power levels in the device, transmit diagnostics, etc. Thereceiver portion of the wireless system or a wireline device can be hungoff in the wellbore using standard type wireline locks landed in landingnipples, or hung off by a slips type arrangement.

In one example the wellbore device is a remotely controllable wellborevalve that can be used to temporarily, or permanently, replace thefunction of a hydraulically operated subsurface safety valve. Referringto FIG. 2, a typical hydraulically actuated wellbore valve is shown. Thevalve 20, which may be a subsurface safety valve, is coupled within aproduction tubing 16. The production tubing 16 extends inside thewellbore to the wellhead system (14A in FIG. 1) and provides a conduitfor fluids to move from selected subsurface formations to the surface.The valve 20 includes features an hydraulic line connection 22 coupledto an hydraulic control line 18 extending to the surface. The hydraulicline connection 22 conducts hydraulic fluid to an actuator 23. Whenpressurized, the actuator 23 provides force to overcome a spring (notshown) which ordinarily maintains a flapper 24 in a closed position(transverse to the cross section of the tubing 16). Thus, the actuator23 opens the valve flapper 24. As explained in the Background sectionherein, failure of the actuator 23 may cause the flapper 24 to remainclosed, thus requiring extensive well workover operations to replace thedefective actuator and/or flapper.

FIG. 3 shows an example remotely operable valve system 30 intended to beinserted into the wellbore and “landed” in the defective hydraulicallyoperated valve 20. The example valve system 30 can be inserted into thewellbore using, for example, armored electrical cable (“wireline”) ortubing conveyance. When the valve system 30 is moved through thedefective hydraulically operated valve 20, the body 30A of the examplevalve will move the flapper 24 of the defective valve 20 to open. Thevalve body 30A may include landing nipples 30B to engage a nippleprofile (not shown) in the defective valve 20. The valve body 30A may besealingly engaged to the defective valve 20 using O-rings or othersuitable sealing elements 30B.

A lower end 30C of the valve body 30A may be suitably shaped to causethe flapper 24 to open. Flow ports 36 may be provided at a selectedposition along the length of the valve body 30A to enable fluid flowthrough the upper part of the valve body 30A while maintaining asuitably sealed enclosure for batteries and control electronics 38. Suchelectronics 38 may include an acoustic transducer (not shown separately)for receiving acoustic commands from the system at the surface, or,alternatively, may include an acoustic or electromagnetic transducer forcommunication with a sonde 42 moved through the tubing 16 using anarmored electrical cable 40. A corresponding transducer 44 in the sonde42 may provide one or two way signal communication between the sonde 42and the valve system 30.

A valve flapper 34 is disposed in the valve body 30A such that uponreceipt of a suitable command or otherwise as will be further explained,the electronics 38 will cause an actuator (not shown) to open or closethe flapper 34.

The wireless communication system explained above with reference to FIG.1 may be configured to transmit command signals to the valve system 30.The valve system electronics 38 may be configured to receive commandsfrom the surface system (see FIG. 1) and generate a signal that operatesthe flapper 34. The flapper 34 is only one example of a valve which canbe used with a valve system according to the invention. Other types ofvalve, for example, a ball valve or a sliding sleeve valve may be usedin other examples, and the illustrated flapper is not intended to limitthe scope of the invention. The valve system 30 should also include a“fail safe” feature, e.g., a spring (not shown) which causes the flapper34 or other valve to automatically close in the event of actuator faultor failure. The valve system 30 may also transmit or store in a localrecording device (not shown separately) certain information that can becommunicated to the surface in response to surface-sent commands.

Referring again to FIG. 1, control unit 11 may be programmed to sendcommands to the valve system (30 in FIG. 3), which could include, forexample, “maintain valve in open position”, “open valve” or “closevalve.” As mentioned above, an auxiliary wireline communication sonde(42 in FIG. 3) may be lowered into the tubing 16 to enable communicationwith the valve system.

Example command configurations and valve system responses may includeone or more of the following. When the valve system is in the openposition, a “maintain valve in open position” signal can be transmittedto the system from the surface at selected time intervals, e.g., every15 seconds. If the downhole valve system electronics (38 in FIG. 3) doesnot detect the maintain valve open command within the pre-determinetime, the electronics could be programmed so that after a selected delay(e.g., 5 seconds) the valve would automatically be closes. After suchclosing, the valve would remain closed, and the system electronics wouldwait for detection of an “open valve” command from the surface (viawireless or using the sonde). The electronics (38 in FIG. 1) could scanfor the open valve command at predetermined intervals, e.g., every 30seconds.

A possible advantage of a valve system configured as explained above isthat if an accident occurs at the surface, or there is externalelectrical power failure or a failure within the wireless valve controlunit (11 in FIG. 1) the downhole valve would not receive the “maintainvalve in open position” command within the predetermined time intervals.The downhole valve would therefore automatically close. The valve willbe opened only upon receipt of the appropriate command fin the surface,as previously explained.

A valve system according to the above description can be retrofittedinto wellbores where an hydraulically or electrically operated valvedoes not function due to failure in the control line or cable from thewellhead to the valve. It is also possible to install the wireless valvesystem as a primary subsurface safety valve in new wells.

While the invention has been described with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments can be devised whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

1. A remotely operable wellbore valve system, comprising: a valveconfigured to be coupled to a wellbore conduit and to selectively closethe conduit, the valve disposed in a valve body configured to open anexisting wellbore valve by longitudinal motion therethrough, the valvebody configured to sealingly engage an interior of the existing wellborevalve; a valve actuator; and a signal receiver in communication with thevalve actuator, the signal receiver configured to detect command signalstransmitted from the Earth's surface and to cause the actuator tooperate the valve in response to detected command signals.
 2. The systemof claim 1 wherein the signal receiver is configured to detect acousticsignals transmitted through wellbore fluid inside the conduit.
 3. Thesystem of claim 1 wherein the signal receiver is configured to detectacoustic signals transmitted along wellbore conduit.
 4. The system ofclaim 1 wherein the signal receiver is configured to detect signalstransmitted from a sonde disposed in the wellbore at the end of anarmored electrical cable.
 5. The system of claim 1 wherein the signalreceiver and the valve actuator are configured to maintain the valve inan open position upon detection of maintenance signals from the surfaceat selected time intervals, and to close the valve if the maintenancesignals are not detected.
 6. The system of claim 1 wherein the valvecomprises a flapper.